Thinking about sway bars? Take a look here for some great information
 

Wonder why upgrading your sway bars is important? Read below for our basic overview of how sway bars work.

Regardless of horsepower, improving the suspension allows you to use all available horsepower more often. This is because you have more control and stability in your setup, which in turn allows you to use that right pedal more. One of the cheapest parts to modify in the suspension, while seeing the most improvement would be to replace, remove, or add Sway Bars.

First and foremost a sway bar is a "part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheels together through short lever arms linked by a torsion spring. A sway bar increases the suspension's roll stiffness—its resistance to roll in turns, independent of its spring rate in the vertical direction."-wiki In a nut shell a sway bar is another spring in your suspension system. The cool thing about this spring is that by adding a stiffer bar you can help reduce how much body roll a vehicle has while still maintaining ride comfort.

The reason I listed replace, remove, or add sway bars is because every car behaves differently. Most vehicle will benefit from replacing 1 or more sway bars with stiffer ones, while others may be more stable by removing the rear bar, or some gain more grip by adding a rear sway bar. Each vehicle and setup is different from the next and it can take time and research to know what is best for what you are looking to do with the vehicle. The best way to decide what you should do is research what others are doing with the same car, ask other members who have experience with suspension, or send me a message. There are a range of bars and bar styles that fit everyone's needs.
When starting to research sway bars you will want to start with finding out how many bars your vehicle comes with and their thickness for reference. When searching for aftermarket upgrades they are usually listed by thickness (15mm, 19mm, 24mm, etc). Bar thickness translates to how stiff the sway bar is. Typically adding a thicker bar than what comes on the car is the choice to make as it helps reduce body roll more. Something to keep in mind though... OEM bars are usually hallow, while aftermarket are usually solid. These means a 15mm Eibach sway bar would be stiffer than your 15mm OEM bar that came on the car. Some sway bars come as "Adjustable" and this allows you to adjust how much force the bar places on the wheel to reduce or add body roll.

Sway bars usually range from $150 - $300 depending on the car and really are a great place to start when improving a vehicle.

If you are looking to get some sway bars take a look here Total Automotive Performance | Auto Parts and Accessories | Shocks | Mufflers | LED Lights

or message me directly.

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I have had a stiffer rear sway bar, removed the stiffer rear sway bar, and reinstalled the stock bar. Then I tried removing just the front sway bar, I don't recommend it, it is very unsafe. Then I tried removing just the rear sway bar, and that actually works pretty good. At speed however gives tremendous oversteer. Finally, I bought the front and rear "soft" sway bars from Cusco. The front bar is a solid 16mm instead of a stock 18mm, and the rear is a hollow 14mm instead of a solid 14mm. The front is 79% as hard as stock, and the rear is 73% as hard as stock. This setup allows me to tune my suspension for more comfort on the street, yet hard cornering when I need it. I haven't taken it on the track since installing them yet, but I look forward to it.

Thanks for the comment KoolBRZ. What else is on your BRZ? Sway bar choice always comes down to what else you are running to get that balance that you need. How wide and grippy the tires you run also changes everything. Suspension is always an interesting element to tune on a car, because there are so many variables involved. Looks like you found the balance you needed with the Cusco bars, which is awesome. I have a feeling you may find them slightly soft once you find your self at higher speeds, but you won't know till you try them out at the track.

Let us know how it goes once you take it out to the track.

I call BS on that. With no rear bar it would be very understeer biased.

Try it. When the car starts to lean over while cornering, the rear camber/toe adjustment rods cause the rear of the car to swing out, steering the car further into the corner, (oversteer). That all depends on alignment as well, of course. Since the cars don't have a solid axle straight across, the rear wheels can actually change angle during a corner, depending on alignment, of course.

There is also the opinion of many that a stiffer front sway bar causes oversteer, while a stiffer rear sway bar causes understeer, and since there wouldn't be any rear sway bar, then the front sway bar would be stiffer then the rear, wouldn't it?

You've got that backwards. A stiffer front roll bar gives the rear end more grip... and thus understeer. A stiffer rear bar gives the front more grip and thus over steer.

Please, please, please... please... please buy this book and read it.
[ame="http://www.amazon.com/How-Make-Your-Car-Handle/dp/0912656468/ref=sr_1_4?ie=UTF8&qid=1432227950&sr=8-4&keywords=race+car+suspension"]How to Make Your Car Handle: Fred Puhn: 0075478000012: Amazon.com: Books[/ame]

and then buy this one. [ame="http://www.amazon.com/Chassis-Engineering-Building-Performance-Handling/dp/1557880557/ref=pd_bxgy_14_img_y"]Chassis Engineering: Chassis Design, Building & Tuning for High Performance Handling: Herb Adams: 0075478010554: Amazon.com: Books[/ame]

If you had read those two books, I would almost garantee that you would not have already been through 5+ coilovers and god knows how many sway bar setups.

[ame="https://www.youtube.com/watch?v=zoICf55jED8"]Top Gear Understeer and Oversteer explained - YouTube[/ame]

Look at the rear suspension. The Toe arm and LCA are almost in plane with each other and the toe arm is shorter. The rear toes in under compression. I'm guessing the actual toe change is minimal.

It is minimal, and toe in increases rearend stability.

You won't see a car company design a car to have rear toe-out under compression very often these days...

- Andy

Flip the logic around and you are good like stated above^

Yeah, for the most part cars come from the factory with understeer built in as it is the safest characteristic for the masses to deal with. While some cars may be more twitchy than others understeer is usually more apparent when pushed to the limit.

You throw wider stickier tires on the FRS/BRZ and you will find understeer not oversteer. Only those OEM pizza cutter Prius tires allow that rear end slip from the factory. Stiffer springs and different sways help correct that issue for the type of setup you would like.

Sorry, this was my point.

Just a slight correction, the toe change will happen under both compression and droop, assuming starting with the LCA totally horizontal. You're right that it'll toe in, increasing stability, though.

In any case, most of us agree that we do not have passive rear wheel steering, and a softer rear sway bar (or no rear sway bar) will not increase oversteer.

I 100% agree with you; I was just restating what you said. :)

we got the bolded AND underlined words, awww snap.